PREPARATION OF INTERMEDIATES OF X-RAY CONTRAST AGENTS Russian patent published in 2018 - IPC C07C235/32 C07C231/12 C07C231/14 

FIELD: chemistry.

SUBSTANCE: invention relates to a process for the preparation of iodinated X-ray contrast agents and, in particular, to the preparation of key intermediate compounds used for the preparation of iodinated X-ray contrast agents. Process for the preparation of an N-acylated monomeric compound selected from 5-acetamido-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide (Compounds A) and N,N'-bis(2,3-dihydroxypropyl)-5-formamido-2,4,6-triiodoisophthalamide (Compound C) includes a step of deacylating the acylated hydroxyl groups by adding Compound B2 to an aqueous solution of a deacylating agent which is an inorganic base. For compound B2, each of X is independently hydrogen or an acyl group, with the proviso that at least one of the X groups attached to the nitrogen atom is an acyl group.

EFFECT: method allows to obtain an optimal yield and to reduce formation of pollutants.

6 cl, 2 ex